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LTT/MTT/HTT TENSION TIES
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Tension Ties are ideal for retrofit or new construction and provide
post-pour, concrete-to-wood connections. The HTT16 provides intermediate uplift loads when
HTT22 loads are not required.
The HTT22 is a single-piece formed tension tie -- no rivets, and a
4-ply formed seat which won't unfold during loading. No washers required. The LTT19 Light
Tension Tie is designed for 2x joists or purlins and the LTT20B is for nail- or bolt-on
applications. The 3" nail spacing makes the LTT20B suitable for wood I-joists if
10dx1-1/2" nails are substituted for the specified 16d's. Use the MTT28B Medium
Tension Tie for heavier connections.
The LTTI31 is designed for wood chord open web truss attachments to
concrete or masonry walls.
MATERIAL: See table
FINISH: Galvanized. MTT28B may be ordered HDG;
check factory.
INSTALLATION:
- Use all specified fasteners. See General Notes.
- Use the specified number and type of nails to attach the strap
portion to the bottom or side of purlin or beam (minimum 4x width (2-2x4 or 4x4), except
LTT19). Bolt the base to the wall or foundation with a suitable anchor; see table for the
required bolt diameter.
- The HTT22 can have a maximum offset of 2" from the stud face to
92 the centerline of the anchor bolt.
- Do not install LTT, MTT tension ties raised off the mudsill.
- See Epoxy-Tie Adhesive System, pages 22 and 23 for tested, load-rated epoxies for anchor bolt options.
CODES: BOCA, ICBO, SBCCI No. NER-393
and NER -432;ICBO 5313; City of LA RR 24818 and RR 25318
| Model
No. |
Material
(Ga) |
Dimensions
|
Fasteners
|
Avg
Ult Tension |
Allowable
Tension Loads |
Deflection
at Highest Allowable Design Load |
| Strap
|
Plate
|
W |
L |
CL
|
Anchor
Bolts |
Nails
|
Bolts
|
(133)
|
(160)
|
| Qty |
Dia |
Nails |
Bolts |
Nails |
Bolts |
| LTT19 |
16 |
3 |
1-3/4 |
19-1/8 |
1-3/8 |
3/4 |
8-16d Sinkers |
-- |
-- |
4250 |
1205 |
-- |
1350 |
-- |
0.107 |
| LTT20B7 |
12 |
3 |
2 |
19-3/4 |
1-3/8 |
1/2, 5/8 or 3/4 |
10-16d |
2 |
1/2 |
8733 |
1750 |
1220 |
1750 |
1460 |
0.164 |
| LTTI31 |
18 |
3 |
3-3/4 |
31 |
1-3/8 |
5/8 |
8-10dx1-1/2 |
-- |
-- |
7807 |
1805 |
-- |
1805 |
-- |
0.125 |
| HTT16 |
11 |
-- |
2-1/2 |
16 |
1-3/8 |
5/8 |
18-16d |
-- |
-- |
13150 |
3480 |
-- |
4175 |
-- |
0.037 |
| HTT22 |
11 |
-- |
2-1/2 |
22 |
1-3/8 |
5/8 |
32-16d Sinkers |
-- |
-- |
13150 |
5250 |
-- |
5260 |
-- |
0.087 |
| MTT28B |
12 |
7 |
2-1/16 |
27 |
1-1/2 |
5/8 or 3/4 |
24-16d |
4 |
/2 |
-- |
4455 |
2150 |
4455 |
2725 |
0.125 |
- Allowable loads for HTT are based on the lower of the 1997 NDS
fastener values or the ultimate load on a steel test jig divided by 2.5.
- 16d sinkers (9 ga x 3-1/4") or 10d commons may be substituted
for the specified 16d commons at 0.85 of the table loads.
- The designer must specify anchor bolt type, length and embedment.
- Allowable loads have been increased 33% and 60% for earthquake or
wind loading with no further increase allowed.
- Bolt values are based on a minimum lumber thickness of 1-1/2".
- See HDA for deflection at highest allowable design load definition.
- If a 1/2" or 5/8" anchor bolt is used for the LTT20B, add a
standard cut washer to the seat. No additional washer is required for a 3/4" anchor
bolt. See table for appropriate anchor bolt sizes.
- HTT Holdowns installed off the plate have a reduced toad (5190 lbs
for HTT22, 4175 lbs for HTT16) and may have larger deflection values.
ADDITIONAL ANCHOR DESIGNS
See SSTB, page 17. Anchor types shown are
made by others and used with Simpson Strong-Tie® holdowns. The design
engineer may specify an alternate anchorage system, provided the anchor diameter is the
same.
See the Prestressed Concrete Institute Design Handbook (Edition 3),
Section 6.5.2.
| Anchor3
Type |
Dimensions
|
Minimum
Concrete Strength (psi) |
Allowable1
Tension Load (133) |
| Dia
|
Min
le2,4
|
de |
Min
End Dist |
| A |
1 |
36 |
2-3/4 |
5 |
2500 |
9795 |
| A |
1-1/4 |
36 |
2-3/4 |
5 |
2500 |
12900 |
| B |
1,1-1/4 |
8 |
8 |
8 |
3000 |
15305 |
- Allowable tension load is for earthquake loading; reduce to 88% for
wind loading.
- Anchor embedment length is based on a single-pour concrete
foundation. Double pour foundation systems, masonry walls and masonry footings must be
evaluated by the designer.
- Anchor bolt B must be ASTM A307; anchor bolt A must be A36 steel or
better.
- Spacing between anchors is 2le min. for anchors in tension at the
same time,
- "A" bolt minimum end distance is for corner with 12"
return only (similar to SSTB28, see Typical Rebar Placement, Corner Installation).
Otherwise, the minimum end distance is le for the full table load.
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